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In this article, we investigate a novel iterative antenna array synthesis method. The method is based on the iterative addition of antenna array elements. After defining the synthesis algorithm, we prove that the discrepancy between the goal and the synthesized pattern converges to the theoretical lower bound in the sense of a certain norm. The algorithm is also extended to iteratively replace already placed elements and for the synthesis of multiple goal patterns with the same array geometry but with different excitations. Some numerical examples are shown to illustrate the convergence properties of the proposed method. Possible applications include circularly polarized patterns, since the algorithm can handle the rotation as well as translation of the antenna elements.

Electromagnetic scattering from propellers of smallsized Unmanned Aerial Vehicles (UAVs) is studied in this work. Previous works have shown that rotating propeller blades produce significant fluctuations of the Radar Cross Section (RCS) in the case when the propeller length is about half a wavelength of the illuminating wave. To some extent, this facilitates both the measurement of the RCS in anechoic chamber and the detection of small-sized UAVs. In the present contribution, these studies are extended to the case of multiple propellers, between which an electromagnetic coupling is expected. The scattered field and the RCS is calculated by means of electromagnetic simulation using an integral equation formulation, and the theory is validated against anechoic chamber measurements.